Norovirus infection can cause the sudden onset of severe vomiting and diarrhea. The virus is highly contagious and commonly spread through food or water that is contaminated by fecal matter during preparation. You can also be infected through close contact with an infected person.

Diarrhea, abdominal pain and vomiting typically begin 24 to 48 hours after exposure. Norovirus symptoms last one to three days, and most people recover completely without treatment. However, for some people — especially infants, older adults and people with underlying disease — vomiting and diarrhea can be severely dehydrating and require medical attention.

Norovirus infection occurs most frequently in closed and crowded environments such as hospitals, nursing homes, schools and cruise ships.

Signs and symptoms of norovirus infection include:

Nausea

Vomiting

Abdominal pain or cramps

Watery or loose diarrhea

Malaise

Low-grade fever

Muscle pain

Signs and symptoms usually begin 24 to 48 hours after first exposure to the virus, and last one to three days. You may continue to shed virus in your feces for up to three days after recovery.

Some people with norovirus infection may show no signs or symptoms. However, they are still contagious and can spread the virus to others.

When to see a doctor

Seek medical attention if you develop diarrhea that doesn't go away within several days. Also call your doctor if you experience severe vomiting, bloody stools, abdominal pain or dehydration.

Noroviruses are highly contagious and are shed in the feces of infected humans and animals. Methods of transmission include:

Eating contaminated food

Drinking contaminated water

Touching your hand to your mouth after your hand has been in contact with a contaminated surface or object

Being in close contact with a person who has a norovirus infection

Noroviruses are difficult to wipe out because they can withstand hot and cold temperatures as well as most disinfectants.

Risk factors for becoming infected with norovirus include:

Having an impaired immune system

Living in a place where food is handled with unsanitary procedures

Living with a child who attends preschool or a child care center

Living in close quarters, such as in nursing homes

Staying in hotels, resorts, cruise ships or other destinations with many people in close quarters

For most people, norovirus infection clears up within a few days and isn't life-threatening. But in some people — especially children and older immunocompromised adults in hospitals or nursing homes — norovirus infection can cause severe dehydration, malnutrition and even death.

Warning signs of dehydration include:

Fatigue

Dry mouth and throat

Listlessness

Dizziness

Decreased urine output

Here's some information to help you get ready for your appointment and know what to expect from your doctor.

What you can do

Write down your symptoms, including when the illness began and the frequency of the vomiting and diarrhea.

Make a list of all your medications, vitamins or supplements.

Write down your key medical information, including other conditions.

Write down key personal information, including any recent changes or stressors in your life

Write down questions to ask your doctor.

Questions to ask your doctor

What's the most likely cause of my symptoms?

What treatments can help?

How can I avoid spreading my illness to other people?

In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask questions during your appointment.

What to expect from your doctor

Your doctor is likely to ask you a number of questions. Being ready to answer them may make time to go over points you want to spend more time on. You may be asked:

When did you or your child first begin experiencing symptoms?

How frequent are the vomiting and diarrhea?

Does the vomit or diarrhea contain mucus, blood or a dark green fluid (bile)

Have you or your child had a fever?

Diagnosis is usually based on your symptoms. But norovirus can be identified by testing a stool sample. If you are immunocompromised or have other health problems, your doctor may recommend a stool test to confirm the presence of norovirus.

There's no specific treatment for norovirus infection, and recovery generally depends on the health of your immune system. In most people, the illness usually resolves within a few days.

It's important to replace lost fluids. If you're unable to drink enough fluids to prevent dehydration, you may need to receive fluids intravenously.

Your doctor also may recommend over-the-counter anti-diarrhea medication if you're under the age of 65.

If your family includes young children, it's a good idea to have commercially prepared oral hydration solution, such as Pedialyte, on hand. Adults can drink sports drinks and broths. Drinking liquids that contain a lot of sugar, such as soft drinks and fruit juices, can make diarrhea worse.

Smaller meals and a bland diet may help limit vomiting. Some foods to consider:

Soup

Starches and cereals, such as potatoes, noodles, rice or crackers

Banana

Yogurt

Broiled vegetables

Norovirus infection is highly contagious. To help prevent its spread:

Wash your hands thoroughly, especially after using the toilet or changing a diaper.

Avoid contaminated food and water, including food that may have been prepared by someone who was sick.

Wash fruits and vegetables before eating.

Cook seafood thoroughly.

Dispose of vomit and fecal matter carefully, to avoid spreading norovirus by air. Soak up material with disposable towels, using minimal agitation, and place them in plastic disposal bags.

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